Direct in cylinder injector for gaseous fuel
A novel in-cylinder fuel injector has been created for internal combustion engines using gaseous fuels such as hydrogen and low-carbon alternatives. This injector enhances the reliability and fuel efficiency of both spark-ignited and compression-ignition engines. The injector's innovative design encompasses a poppet-style valve for fuel injection and a fuel supply valve to govern fuel flow. Furthermore, it incorporates a distinct lubrication system that caters to the valve, seat, and sliding surface. Additionally, the injector includes valve actuators and a control system, effectively managing fuel injector actuation, injection timing, quantity, and valve actuation sequence. Notably, the design also integrates a lubrication system with a control valve.
This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63/416,630, entitled “Direct In cylinder injector for gaseous fuel,” filed Oct. 17, 2022, the disclosure of which is incorporated by reference in its entirety.
BACKGROUNDThe embodiments described herein relate to a direct in cylinder fuel injector for hydrogen and other low carbon gaseous fuel. More specifically this invention relates to an injector design that has higher combustion efficiency and maintains high power density when using hydrogen or low carbon gaseous fuel in an internal combustion engine. The injector design provides protection for a hydrogen or low carbon gaseous fuel that does not provide lubricity. The injector can be used in the hydrogen fuel cell by providing continuous, and modulated hydrogen flow with a reliable fuel shut-off system.
The transportation sector accounts for 28% of greenhouse gas emissions, making it essential to embrace new fuels like hydrogen, a zero-carbon fuel, to address this environmental challenge. Among the solutions available, hydrogen internal combustion engines play a significant role. A key component needed for these engines is a reliable hydrogen fuel injector delivering high injection pressure for efficiency.
Gaseous fuels lack the inherent lubrication found in liquid fuels, and as a result, existing injectors suffer from lubrication deficiencies. In certain cases, the operator resorts to manual lubrication by introducing a small amount of engine oil into the injector's inlet each day before engine startup. Nonetheless, these systems and procedures are far from feasible for commercial applications.
In gaseous fuel injectors, a challenge arises due to the occurrence of metal-to-metal contact when the valve is seated, resulting in accelerated wear of the contact surface. Various approaches, including the use of hardened materials and the reduction of the valve closing speed, have been explored to address this issue, but these attempts have yielded only marginal improvements. This problem becomes particularly pronounced in the case of hydrogen injectors, where substantial quantities of hydrogen must be delivered to match the energy output of liquid fuels. Consequently, larger-sized injectors with high valve lift are required, exacerbating the wear issue.
There is a need for improved injectors and systems for injecting gaseous fuels in internal combustion engines. A poppet valve provides a larger opening area, to deliver the high volumetric flow of hydrogen. The larger opening area reduces the valve lift, which lowers the contact force between the valve and the seat. The larger opening area provides a means for optimizing injection timing and volume to improve combustion efficiency.
Lubrication of the valve and seat is provided by a dedicated passage and has a control valve that regulates the lubricating oil supply. The flow of lubricant is achieved when the poppet valve is seated and high pressure hydrogen is shut off by the fuel supply valve and the gas supply drilled passage in the poppet valve shoulder.
The fuel injector design allows the presence of high gas pressure in the poppet valve area only during the injection period when the valve is open
This eliminates a leakage path for hydrogen thus enabling high gas supply pressures above 10,000 psi. Higher pressure offers higher combustion efficiency for the internal combustion
Accordingly what remains needed in the art is a direct in cylinder high pressure injector that will match the reliability of a state of the art liquid fuel injector and optimum combustion efficiency.
SUMMARYA direct in cylinder compressed gas injector with poppet valve and complementary valve seat. Poppet valve with a shoulder and passage that interfaces with the injector supplying gas to the injector. In another aspect, a fuel supply valve connects to the injector poppet valve when activated. Controlled lubrication of injector and fuel supply valve. A control system arrangement to regulate the supply and end gaseous fuel injection. Another aspect of using a dual fuel nozzle supplying gas and pilot diesel like fuel injector. A pressure transducer for injector prognostics.
The present invention is a direct in cylinder gas injector for spark ignited and compression ignition engines.
Referring to
Optimized oil flow into the injector is achieved by modulating the injector valve 105, in
Claims
1. A compressed gas injector for mounting directly in a cylinder of an internal combustion engine, comprising:
- a poppet valve;
- an injector valve stem shoulder coupled to the poppet valve with drilled passages to supply or shut off compressed gas into the compressed gas injector in response to movement of the poppet valve; and
- a seat,
- wherein the poppet valve defines complementary seat angles between 25 degrees and 65 degrees.
2. The compressed gas injector of claim 1, further comprising:
- a valve spring size reduction to seat the poppet valve against the seat as pressurized gaseous fuel is shut off above an area associated with the seat.
3. The compressed gas injector of claim 1, further comprising:
- a fuel supply valve that opens to send pressurized gaseous fuel to the injector and to shut off pressurized gaseous fuel before the valve seat closes to reduce the high pressure gas above the valve seat when the injector is not active.
4. The compressed gas injector of claim 1 further comprising:
- a lubrication passage feeding oil to the seated injector valve cavity with low pressure to provide an oil film between the contact surface to prevent metal to metal contact and reduce wear of the sealing surface.
5. The compressed gas injector of claim 1 further comprising:
- a control valve to regulate the flow of lubricating oil to the injector, fuel supply valve, and spring cage areas which also lubricates through the valve stem seal.
6. The compressed gas injector of claim 1 comprising:
- a hydraulic or piezo actuator that controls injector valve opening, valve lift, and opening and closing rate to lower the valve seating velocities minimizing seat wear.
7. The compressed gas injector of claim 1 comprising:
- a hydraulic or piezo actuator that controls the fuel supply valve to supply and shut off pressurized gaseous fuel to the injector for maintaining low trapped gas pressure and gas leakage path in the injector.
8. The compressed gas injector of claim 1 comprising:
- an injector nozzle attachment to direct the gaseous fuel jet into the engine to optimize the combustion system.
9. The compressed gas injector of claim 1 comprising:
- a pressure transducer located in the fuel supply valve for diagnostics and utilizing machine learning for prognostics.
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Type: Grant
Filed: Oct 16, 2023
Date of Patent: Oct 1, 2024
Inventor: Budhadeb Mahakul (Naperville, IL)
Primary Examiner: Jacob M Amick
Assistant Examiner: Charles J Brauch
Application Number: 18/487,684